Kenji Masunaga

Kurume University, Куруме, Fukuoka, Japan

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Publications (17)27.29 Total impact

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    ABSTRACT: Objective Warfarin is known to interact with many drugs; however, there are currently no descriptions of an interaction with linezolid in the literature. It was recently brought to our attention, however, that several warfarin-medicated patients have experienced an increase in the prothrombin time international normalized ratio (PT-INR) following the administration of linezolid. We therefore performed a retrospective survey in order to investigate the possibility of an interaction between warfarin and linezolid. Methods The survey items included age, gender, underlying disease, type of surgery, type of infectious disease, duration of linezolid administration, laboratory values and the dose of warfarin. The PT-INR was observed over time before treatment and at days 4 or 5 and 10, completion and one week after the end of concomitant therapy. Patients The subjects included six patients who were recovering from recent heart-related surgery. Results The PT-INR increased from 1.62±0.32 before concomitant linezolid administration to 3.00±0.83 at day 4 or 5 after concomitant administration (p<0.01) and significantly decreased from 1.65±0.45 at the completion of the regimen to 1.26±0.1 one week later (p<0.05). With respect to the relationship between the dose of warfarin and the PT-INR in five cases, the PT-INR increased following concomitant linezolid treatment in all cases. Conclusion Although it has been reported that linezolid does not influence the metabolism or protein binding of warfarin, our data showed potential drug interactions between warfarin and linezolid. Our data suggest that PT-INR monitoring after the completion of concomitant warfarin and linezolid therapy is important.
    Internal Medicine 01/2015; 54(5):459-64. DOI:10.2169/internalmedicine.54.3146 · 0.97 Impact Factor
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    ABSTRACT: A methicillin-resistant Staphylococcus aureus (MRSA) outbreak occurred in an advanced emergency medical service center between 2010 and 2011. Our objective was to evaluate the status of the MRSA outbreak, as monitored by molecular analysis. Twenty-eight MRSA strains were isolated from blood samples from 11 patients, from other specimens (pharynx, nasal cavity, etc.) from 12 patients, from two environmental samples, and from the skin, middle nasal meatus, and urine of one patient each from other wards. Pulsed-field gel electrophoresis (PFGE) was performed to evaluate horizontal transmission. Molecular typing by PFGE showed that the 28 MRSA strains presented 7 patterns in total, and that 11 of the MRSA strains had the same PGFE pattern. Unselective use of intranasal mupirocin ointment, MRSA monitoring for new inpatients, and prevention of direct or indirect contact infection were performed. However, the number of inpatients with MRSA did not quickly decrease, and additional molecular typing by PFGE showed that 10 of 19 MRSA strains found (5 of 6 from blood, 5 of 13 from other specimens) were the same as those found previously. Lectures and ward rounds were performed repeatedly, and staff participation in ward rounds was suggested. Finally, the number of inpatients with MRSA significantly decreased more than 6 months after the intervention. Although the MRSA outbreak was thought to have ended, follow-up molecular typing by PFGE showed that horizontal transmission persisted. Our data suggest that various combinations of infection control measures are essential when dealing with an MRSA outbreak, and monitoring by molecular analysis using PFGE is useful to identify the status of the outbreak.
    Journal of Infection and Chemotherapy 03/2013; 19(5). DOI:10.1007/s10156-013-0587-8 · 1.38 Impact Factor
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    ABSTRACT: Hospital renovation projects pose risks of invasive infection by fungi from dust that is blown about during the period in question. Control measures to reduce the amount of dust during hospital renovation are thus necessary. Currently, no study has compared different control measures for effectiveness through more than one period of renovation. In this study, we examined the capacities of two control measures of weatherstripping (0.15 mm poly film and adhesive tape) to reduce the amount of blowing dust during two different hospital renovations (in 2008 and 2009). The amount of dust in the air of the hospital before and during the renovation was measured about once a week in both 2008 and 2009, and the between-year and within-year differences were tested. Our study revealed that the weatherstripping used in 2009 (adhesive tape) was significantly more effective than the measures taken in 2008 (0.15 mm poly film) to reduce the amount of dust during the renovations (p < 0.001), while in both years the amount of dust became significantly higher during the renovations than before the renovations. Differences in the effectiveness of weatherstripping during renovations between floors of the hospital were not significant in both 2008 and 2009. The number of Aspergillus-positive samples did not significantly increase compared with the number observed before the start of the hospital renovations (2006-2007) in 2008 and 2009, respectively. The weatherstripping potentially reduced the associated risk of airborne fungal infection.
    Journal of Infection and Chemotherapy 10/2010; 16(6):431-5. DOI:10.1007/s10156-010-0173-2 · 1.38 Impact Factor
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    ABSTRACT: A 54-year-old Japanese man without underlying disease developed pneumococcal bacteremia and meningitis after traveling to the Philippines. The isolate demonstrated high affinity to the lung and invasiveness in vivo. The international travelers can import indigenous high virulent strains even if the bacterium is commonly isolated in the home country.
    Journal of Travel Medicine 01/2010; 17(1):63-5. DOI:10.1111/j.1708-8305.2009.00377.x · 1.53 Impact Factor
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    ABSTRACT: Adrenocorticotropic hormone (ACTH) has been the first-line drug for the treatment of West syndrome, although the therapy has various adverse effects. ACTH depresses resistance to a variety of bacterial, viral, protozoal, and fungal agents. The timing of the various vaccinations is delayed after ACTH therapy in Japan, because the immune system is believed to be affected for approximately 6 months. However, the duration of the effect of ACTH on the immune system is not known. Therefore, we examined changes in the immunity levels before and after ACTH therapy. We measured white blood cell counts, lymphocyte counts, T/B cell counts, CD4(+) and CD8(+) T cell counts, CD 4/8 ratio, lymphocyte blastoid transformation by PHA or Con-A, and the levels of IgA, IgM, and IgG before, immediately after, and 1, 3, 6, and 12 months after ACTH therapy. The lymphocyte counts and CD4(+) T cell counts were significantly decreased immediately after and at 1 and 3 months after the therapy, and did not return to the previous levels even at 6 months and 12 months after ACTH treatment; however, these levels returned to within normal limits (within the 95% confidence interval). Immunoglobulin levels did not change after the ACTH therapy. Helper T cells were more depressed than cytotoxic T cells after ACTH therapy.
    Brain & development 11/2009; 31(10):739-43. DOI:10.1016/j.braindev.2008.11.007 · 1.54 Impact Factor
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    ABSTRACT: MICs of penicillin G, erythromycin, clarithromycin, clindamycin, azithromycin, and telithromycin were tested for 189 clinical isolates collected during 2002 to 2005 from children in southwestern Japan. Serotyping and polymerase chain reaction for presence of erm(B) and mef(A) were performed. All strains with erm(B) + mef(A) were analyzed by pulsed-field gel electrophoresis (PFGE) and compared to 3 global clones: Spain(23F)-1; Spain(9V)-3 and its variant -14; a South Korean strain same as Taiwan (19F)-14 clone and 5 strains with erm(B) + mef(A) from other countries. Of the 173 macrolide-resistant (erythromycin MIC > or =0.5 microg/mL) strains, 104 (60.1%) had erm(B), 47 (27.2%) had mef(A), and 22 (12.7%) had erm(B) + mef(A). Strains expressing erm(B) or both erm(B) and mef(A) had high macrolide MIC(90)s (>64 microg/mL), except telithromycin (MIC(90), 0.25 microg/mL). Of the 22 erm(B) + mef(A) strains, 10 had 4 distinct PFGE patterns and were mainly serotype 6B clones, which differed from those described in previous reports; 5 other strains had unique profiles.
    Diagnostic Microbiology and Infectious Disease 09/2008; 62(1):16-22. DOI:10.1016/j.diagmicrobio.2007.10.013 · 2.57 Impact Factor
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    ABSTRACT: Streptococcus bovis very occasionally causes rarely sepsis, endocarditis, and meningitis in newborns and the elderly. We report the case of infant meningitis caused by S. bovis despite normal cerebrospinal fluid (CSF) findings at the first CSF examination. A 77-day-old boy with 21-trisomy and patent foramen ovale and seen for a high fever underwent blood examination and lumbar puncture due to toxic appearance despite a lack of meningeal signs, and was admitted. His CSF findings were normal and he was given intravenous ceftriaxone against potential bacteremia. He had systemic seizures with continuous fever for 2 days after admission and a second CSF examination. Gram-positive coccus grew from his CSF at the first examination, and CSF cells from the second lumbar puncture increased to 4060/tL (86% neutrophils), so vancomycin was added against potential enterococcal meningitis. S. bovis was finally grown from the first CSF, ceftriaxone discontinued, and intravenous ampicillin added. He recovered after 20 days of antibiotic administration. S. bovis becomes a potential pathogen for meningitis in infants, and must be considered as a cause of meningitis despite its very rarity. CSF findings at the first lumbar puncture may be normal for meningitis in newborns and infants at the first CSF examination, so we must be very careful in the diagnosis of bacterial meningitis even with normal CSF findings, and considered antibiotic treatment against potential bacterial meningitis.
    Kansenshogaku zasshi. The Journal of the Japanese Association for Infectious Diseases 02/2008; 82(1):26-9. DOI:10.11150/kansenshogakuzasshi1970.82.26
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    ABSTRACT: Dipylidium caninum, the dog tapeworm, is a common intestinal cestode of domestic dogs and cats, but few cases have been reported of human infection by this parasite in Japan. We repot a case of D. caninum infection in a 17 month-old girl, who sometimes had symptoms of abdominal pain, diarrhea, and dysphoria at night. Her mother noted the appearance of small white worms in her stool, and she was seen by a local pediatrician. Despite antiparasitic therapy wiht pyrantel pamoate, the problem persisted and was eventually referred for further workup to Kurume University Hospital. The diagnosis was made by microscopic examination of the excreted proglottids, which contained characteristic egg capsules. She was successfully treated with a singledose of praziquantel and four adult parasites were recovered. The longest intact worm was 32cm. Her family had household pets (a dog and a cat). The pets were seen by the local veterinary and both were evidenced D. caninum. Humans, primarily children, become infected when they accidentally ingest fleas. Parents usually find proglottids as multiple white objects, often described as cucumber, melon, or pumpkin seeds, in stool, diapers, or on the perineum. Most general practitioners and pediatricians may treat children with enterobiasis (pinworm) infection, and in case the treatment fails, other parasite infection should be considered such as this worm. A history of dog or cat pets, fleas, and flea bites may be important clues to diagnosis. Pets found to be infected should also be treated.
    Kansenshogaku zasshi. The Journal of the Japanese Association for Infectious Diseases 08/2007; 81(4):456-8. DOI:10.11150/kansenshogakuzasshi1970.81.456
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    ABSTRACT: An epidemic of aseptic meningitis caused by human echovirus 9 (E-9) occurred in the summer of 1997 in northern Kyushu, Japan. Sequences of genome position 2504-3358, which encoded a part of VP1, of the nine isolated viruses were determined. An RGD motif and B-C loop were found in all. They were almost identical and closely related to the virulent strain Barty.
    Microbiology and Immunology 02/2001; 45(10):717-20. DOI:10.1111/j.1348-0421.2001.tb01306.x · 1.31 Impact Factor
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    ABSTRACT: Because synthetic short peptides bearing critical binding residues, can chemically mimic the folded antigenic determinants on proteins, short synthetic peptides can generate antibodies that react with cognate sequences in intact folded proteins. According to this mimotope theory, we produced site-specific antibodies by immunization with short peptides which overlapped each other and covered the entire protein, and used them for domain mapping of influenza virus RNA polymerase (antibody-scanning method). We also used a tagged-epitope and its monoclonal antibodies for topology mapping of clathrin light chains in clathrin triskelions by electron microscopy. Both methods using specific epitopes in combination with their antibodies enable us to determine the domains of interesting proteins systematically without the need to generate monoclonal antibodies or mutant proteins.
    Current Protein and Peptide Science 12/2000; 1(3):303-8. DOI:10.2174/1389203003381360 · 2.33 Impact Factor
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    ABSTRACT:  To obtain reagents to functionally map the PA protein, we produced monoclonal antibodies specific to this protein. Twenty-two monoclonal antibodies reacting with PA protein in ELISA were divided into 10 groups on the basis of competitive binding patterns to this protein. Of these, seventeen monoclonal antibodies bound to PA polypeptide spanning amino acids 101–400 and three bound to that of amino acids 518–600, while the other two did not react with any PA polypeptides tested with the exception of the intact PA. Among these monoclonal antibodies, only five reacted with PA in A/PR/8/34 virus-infected cells in indirect immunofluorescence assay. Thus, we obtained monoclonal antibodies that recognize at least 10 distinct regions of the PA molecule. These monoclonal antibodies should be useful in dissecting functions of the PA protein.
    Archives of Virology 04/2000; 145(5):957-964. DOI:10.1007/s007050050687 · 2.28 Impact Factor
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    ABSTRACT: To obtain reagents to functionally map the PA protein, we produced monoclonal antibodies specific to this protein. Twenty-two monoclonal antibodies reacting with PA protein in ELISA were divided into 10 groups on the basis of competitive binding patterns to this protein. Of these, seventeen monoclonal antibodies bound to PA polypeptide spanning amino acids 101-400 and three bound to that of amino acids 518-600, while the other two did not react with any PA polypeptides tested with the exception of the intact PA. Among these monoclonal antibodies, only five reacted with PA in A/PR/8/34 virus-infected cells in indirect immunofluorescence assay. Thus, we obtained monoclonal antibodies that recognize at least 10 distinct regions of the PA molecule. These monoclonal antibodies should be useful in dissecting functions of the PA protein.
    Archives of Virology 02/2000; 145(5):957-64. DOI:10.1007/s007050050682 · 2.28 Impact Factor
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    ABSTRACT: Monoclonal antibodies against the PB2 of A/Puerto Rico/8/34 (A/PR/ 8/34) (H1N1) were prepared in order to define the functional domains of the RNA polymerase of influenza virus. The fifteen monoclonal antibodies that were generated were divided into 4 groups on the basis of ELISA binding to PB2 or its peptide fragments. Six Group I antibodies that bound to the PB2 N-terminal region (amino acids 1-104) did not inhibit transcription by the viral ribonucleoprotein complex. A single Group II antibody recognizing the region of amino acids 206-259 inhibited ApG-primed transcription. Groups III and IV antibodies bound to the C-terminal region of amino acids 660-759. Of these, Group III antibodies inhibited transcription. The present results identify multiple monoclonal antibody binding domains in PB2, two of which, when bound by antibodies, negatively affect viral RNA transcription.
    Archives of Virology 02/2000; 145(9):1947-61. DOI:10.1007/s007050070068 · 2.28 Impact Factor
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    ABSTRACT: Influenza virus RNA polymerase with the subunit structure PB1-PB2-PA is involved in both transcription and replication of the RNA genome, including the unique cap-I-dependent RNase activity. To map the important domains for RNA polymerization, cap-I-dependent RNase, and cap-I-binding activity, we generated site-specific antibodies against overlapping 150-amino-acid peptides that cover each entire subunit. Monospecific antibodies against each subunit inhibited RNA synthesisin vitro.Those against PB1 and PB2 inhibited the cap-I-dependent RNase activity, but those against PB2 alone slightly inhibited the cap-I-binding activity. Antibodies against the N-terminal amino acids 1–159 of PB2 that overlap the PB1-binding site on PB2 and the C-terminal amino acids 501–617 of PA that overlap the putative nucleotide-binding site and PB1-binding site on PA inhibited RNA polymerizing activity as well as monospecific antibodies. Those against the N-terminal (amino acids 1–159); the central region (amino acids 305–559) of PB2, where a part of the cap-binding domain predicted previously is localized; the N-terminal (amino acids 1–222) of PB1; and amino acids 301–517 and 601–716 of PA inhibited the cap-I-dependent RNase activity. The cap-binding domain on PB2 could be mapped in amino acids 402–559, where one of the cap-binding domains mapped previously overlapped.
    Virology 04/1999; 256(1-256):130-141. DOI:10.1006/viro.1999.9625 · 3.28 Impact Factor
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    ABSTRACT: The nucleotide sequences of the genome RNA encoding the RNA polymerase and the 3' non-coding region (NCR) of bovine enterovirus (BEV) serotype I Japanese isolate, MZ468, were determined. The genetic distance between the two BEV serotype I strains, MZ468 and VG-5-27, was calculated by pairwise comparison of nucleotide sequences. The synonymous substitution rate was high (1.40 x 10(-2)/site/year), and of the same order as those of influenza virus HA, HIV-1 gag and env, and enterovirus 70 VP1 genes.
    Archives of Virology 02/1998; 143(4):815-21. DOI:10.1007/s007050050333 · 2.28 Impact Factor
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    ABSTRACT: Human papillomavirus (HPV) types 16 and 6b E7 proteins and their chimeric or mutant proteins were analyzed for oligonucleotide-binding activity by surface plasmon resonance-based biomolecular interaction analysis. The results indicated that type 16 E7 protein has stronger nucleic acid-binding activity than that of type 6b E7 protein. In addition, the results also indicated that the zinc finger-like motif in the C-terminal region of the type 16 E7 protein plays an important role in this activity.
    Journal of Virological Methods 06/1996; 59(1-2):173-6. DOI:10.1016/0166-0934(96)02040-X · 1.88 Impact Factor
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    ABSTRACT: An experimental rat model for vertical transmission of human T cell leukemia virus type I (HTLV-I) was used to examine whether the infection of offspring derived from HTLV-I carrier rats could be established during the suckling period. MT-2 (2 x 10(7)) cells were injected into 5-week-old rats twice, at 2-week intervals. HTLV-I infected or non-infected female rats were mated with HTLV-I carrier male rats. The titer of serum antibodies against HTLV-I in the offspring derived from non-infected dams was less than 1:16 by the agglutination test during the suckling period. The serum antibodies of the offspring derived from the infected dams was less than 1:32 at 1 day after birth and increased steadily to 1:2048 at 14 days. However, the HTLV-I proviral sequences were not detected in any organs of the offspring during the suckling period as determined by the nested double polymerase chain reaction (PCR). These findings indicate that maternal antibodies against HTLV-I were not readily transmitted through the placenta and that the anti-HTLV-I antibodies in the offspring came from the milk of the dams. Furthermore, the HTLV-I infection in the offspring that was derived from the carrier dam may not be established during the suckling period but after weaning.
    The Kurume Medical Journal 02/1996; 43(1):1-9. DOI:10.2739/kurumemedj.43.1